in many regions, daffodils bloom marks the unofficial beginning of the spring season. Credit: ISNSjust in time for the birds and the bees to start buzzing, flowers and trees in some way know when to open their buds or beginning of flowering. But the exact way that plants obtain their alarm clock has been something of a mystery.
"Why should plant care?". "The general answer to this is that there are many situations where it is important not to do something and delayed until spring came,", said Richard Amasino, Professor of Biochemistry at the University of Wisconsin-Madison. "Trees want to ensure that their buds are protected until the spring."
Sibum Sung, molecular biologist at the University of Texas Austin has an idea of works of this measure of protection at the cellular level. He discovered a particular molecule in plants which gives them the remarkable capacity to recall the winter and bloom on schedule in the spring. Sung published its findings in December last in the journal Science Express.
While digging through the DNA of a small cabbage-like plant called Arabidopsis, Sung and a colleague have discovered that the production of a special molecule could be enabled or disabled by a string of genetic material. When the plant gets comfortable for winter, this molecule is not produced, stifling the ability of a plant to create flowers. But after 20 days of constantly cold weather, production of the molecule gets turned on, another gene to stop repressing flowering and begin to prepare for the spring of signaling. The plant takes another 10-20 days to the first itself to warmer temperatures. Without the 20 days of frost, the molecule would not be produced, even if there is a brief spike in the thermometer reading.
Sung the hypothesis that, for millions of years of evolutionary, this molecule - called COLDAIR - has created a sort of memory cell in generations of plants, letting them know that a month of the winter has come and gone, and now they can begin to prepare for the spring.Of course, the mysteries remain. Sung admits that his team continues to work on issues as the way in which the factory knows that temperatures have been low for at least 20 days."Moreover, we know that there are several things cold, but how?". That we don't really know yet, "said Sung.
The genetic pathways involved are different for each type of plant, said Amasino, but the type of memory clock is similar. The reason may have to do with the early evolution of plants."Flowering plants had already evolved and changed 150 million years ago, when the Earth was a quite different place, Amasino has." At this time, the Earth was much warmer, and the Atlantic Ocean didn't even exist yet. "If it is relatively recently that plants had to cope with the winter", he said.
The kind of answers plants developed cold during the one hundred million years is produced independently, said Amasino - and this is one of the reasons that different plants have unique systems to deal with winter. "One of the plant for the future research objectives are to explore how these systems evolved in different species of plants," said Amasino.
When changes in the climate of the planet more quickly, it may sometimes be difficult for plants to follow. Researchers are studying plants that are open earlier in the season, according to Ove Nilsson, Professor at the Centre of sciences Umea plant in Umea in Sweden. He said that another problem with the start of spring is that plants get out of sync with their pollinating insects."This could potentially be catastrophic for plants as these flowers can freeze to death," said Nilsson.
But as there is winter, nature will keep the pressure on the whole an alarm clock of spring and the plants open once more.More information: Vernalization-Mediated epigenetic silent by a non-coding RNA long intronic, January 7, 2011 Science: Vol. 331 No. 6013 pp. 76-79. DOI: 10.1126/science.1197349
0 comments:
Post a Comment